When a lot of user equipments (UE for short) simultaneously perform access or request services, congestion is caused due to access from a network side or insufficient service resources, or when the network side considers that it is necessary to prohibit access from some terminals or refuse to provide a service for some terminals, the network side may enable an access control mechanism to restrict the access from or service provided for the terminals.
As more UEs access a network, packet switching (PS for short) traffic of a small packet becomes more frequent, and a state of UE is also converted frequently, followed by an explosive increase of PS signaling. To reduce a signaling burden on the network, the PS traffic of the UE is generally set to be always-on, that is, the UE is configured to be in a cell paging channel (CELL_PCH for short) state or a registration area paging channel (URA_PCH for short) state. In this way, once the UE accesses the network, whether there is PS traffic or not, the UE is configured to be always-on, and initiation of the PS traffic is not restricted. Because network resources, for example, resources required by circuit switching (CS for short) traffic, are limited, a normal service of another UE is restricted, and therefore a more flexible access control mechanism needs to be introduced on the network side.
In the prior art, control is performed by using an access class barring (ACB for short) mechanism. When there is traffic congestion, to ensure that UE of each access class can fairly share system resources, an access control parameter needs to be frequently updated; and each time the access control parameter is updated, the UE needs to be first notified, by using a message named paging type 1 or a system message change indication, that a system message changes. However, when the network is congested, the signaling burden on the network may be further aggravated.